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  <meta charset="UTF-8">
  <title>const常量/只读变量的使用</title>
  <script type="text/javascript">
    //常量
    const PI = 3.14;
    //如果修改会报错invalid assignment to const 'PI'
    //PI = 3.1415926;
    console.log(PI);
  </script>
</head>
<body>

</body>
</html>
